bug: /tmp directory not cleaned up

[David Palmer]

When solve-field runs, it leaves behind a file tmp.sanitized.<random> in the temporary directory.

This file should be cleaned up like all the other temporary files it produces.

Also, if the requirements to generate kmz files are not properly installed (so that solve-field chokes on the kmz generation) the kmz-related debris remains in the tmp directory.

(Tested on 0.40 Linux and 0.43 Mac)

(I apologize if there is some other bug-tracker address to use instead of the forum.)